What is CVE-2026-56099?

CVE-2026-56099 is a medium-severity vulnerability in Openbsd Src, classified under Out-of-bounds Read. CVSS score: 5.3/10. Published 2026-06-18.

How severe is CVE-2026-56099?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Out-of-bounds Read in Openbsd Src

CVE-2026-56099

OpenBSD before commit 6a23123 (2026-06-18) contains an out-of-bounds read vulnerability in the mpls_do_error function within sys/netmpls/mpls_input.c that allows remote attackers to disclose kernel stack memory by sending crafted MPLS fram…

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

Affected products

Openbsd Src — versions 0

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

disclosure@vulncheck.com (technical-description, exploit)
disclosure@vulncheck.com (patch)
disclosure@vulncheck.com (third-party-advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2026-56099?: CVE-2026-56099 is a medium-severity vulnerability in Openbsd Src, classified under Out-of-bounds Read. CVSS score: 5.3/10. Published 2026-06-18.
How severe is CVE-2026-56099?: Medium severity. CVSS v3 base score is 5.3 out of 10.